Unable to start Kubuntu VM with AMD-V

Description

I upgraded the Virtualbox from v1.6.0 to v1.6.2, and tried to enable the AMD-V to test a issue which I reported as the ID#1510. I found the AMD-V feature is not stable. I active the VM 4 times and only one time is success. The system environment I used aer sumarized as below.

Thanks very much for your reponse. I only start one VM. The sytem would become no response and the screen is blank for a long time. After 3~5 minutes, I close the window to terminated the VM. If you need more tests, I will help do it.

I upgraded the Virtualbox from v1.6.2 to v1.6.4, and tried to enable the AMD-V to test a issue which I reported as the ID#1721. I run the test 5 times. I found the VM would not start successfully in the two rounds of the 5 tests. The log information is uploaded in issue #1934.